The present disclosure relates to an image forming apparatus for forming an image on a sheet.
A network-compatible image forming apparatus such as a complex machine, a copier or a printer is provided with a network interface for performing communication with a communication device such as a personal computer through a communication network.
Some of image forming apparatuses of this type are further provided with a USB (Universal Serial Bus) interface for performing communication with a communication device in accordance with USB standards.
Such an image forming apparatus has a sleep mode in which power consumption of the image forming apparatus is suppressed. The image forming apparatus preferably supplies operating power to the network interface and the USB interface in the sleep mode for user convenience. When either one of the network interface and the USB interface receives a print job, it is preferable to perform image formation after a transition is made to a normal mode in which the power consumption of the image forming apparatus is not suppressed.
However, since the USB interface more frequently performs communication with the communication device than the network interface, e.g. Ethernet (registered trademark), it consumes more power than the network interface. Specifically, a system of the USB interface performs a process such as connection confirmation of the communication device by automatically and regularly performing communication with the communication device as a connection destination. Thus, even if the USB interface does not perform communication to execute a user's request, e.g. transmission and reception of print data, the system automatically performs communication. As a result, the power consumption of the USB interface is larger than that of the network interface.
Generally, the network interface is more frequently used by a user than the USB interface. Thus, there is a higher necessity to set the network interface in an operative state than to set the USB interface. Further, it is stipulated to supply operating power to the network interface when in the sleep mode by a TEC (Typical Electricity Consumption) measurement method of ENERGY STAR (registered trademark) which is standards for power saving recommended by the US Environment Protection Agency (EPA).
Thus, there is known an image forming apparatus which supplies operating power to a network interface while stopping the supply of operating power to a USB interface when in a sleep mode.
Unless the operating power is supplied to the USB interface when in the sleep mode, the USB interface cannot receive a print job since being set in a stopped state. Thus, even if a user tries to cause the image forming apparatus to perform the print job using a communication device connected to the USB interface during the sleep mode, the image forming apparatus cannot be transitioned to a normal mode in which a printing operation can be performed.
The image forming apparatus cannot return to the normal mode and perform image formation under such a circumstance, which is inconvenient for a user who wants to let the image forming apparatus perform image formation using the communication device connected to the USB interface.
If the operating power is supplied to both the network interface and the USB interface when in the sleep mode, user convenience is improved, but there is a problem in terms of suppressing power consumption since the USB interface has high power consumption.
To solve the above problem, an object of the present disclosure is to provide an image forming apparatus capable of reducing power consumption while maintaining user convenience.